In recent years, nylon line type vegetation cutters or trimmers have become extremely popular with homeowners, gardeners, and persons needing to cut grass, weeds, and the like. Because of the relative safety of such devices, compared to blade type cutters, their popularity is all the greater.
In general, these devices comprise a long handle on which is mounted an engine, either gasoline or electric powered. The output of the engine is connected to a spool so as to cause the spool to rotate at a high speed.
Wound upon the spool is a nylon, monofilament line, and the end of the line projects generally radially outwardly from the spool, a distance typically on the order of 4-12 inches. As the spool, and the projecting end of the line, rotate at high speed, the line acts to "cut" any grass or other small stalk vegetation which it encounters. Since the line is neither sharp nor rigid, as in the case of a blade, should it encounter any obstruction such as a larger tree or stalk, concrete walkways, shoes, or the like, the line simply passes by the obstruction without significant damage to either the engine or the tool, or the obstruction itself.
However, the line is eventually worn or broken both by the "cutting" action and by contact with such obstructions, and these types of tools are provided with means for automatically releasing an additional length of line from the spool so the cutting or trimming work can continue uninterrupted.
Over a period of time, the line is used up and is usually replaced, either by replacing an empty spool with a new one or by rewinding new line onto the old spool.
In many of the more powerful cutters of this type, the line is wound on such a spool so that two ends of line are available for the cutting action, the two ends projecting radially in diametrically opposed directions. In such cases, the cutter is even more efficient. Generally, however, this type of tool uses a more powerful motor since the required rotational force is greater.
In the past, the fully wound replacement spools for such vegetation cutters tend to be considerably more expensive than the line itself. As a result, many users prefer to simply buy the line in bulk form and rewind it onto their own spools. This is particularly true in the case of commercial use of this equipment. However, the spools presently available tend to increase the amount of line wasted by the user.
For example, both in the case of the single and double end trimmers, the replacement line ends are simply inserted into holes in the hub of the spool and then the line is wound around the hub. The bend in the line, as it emerges from the hole and turns approximately 90.degree. to wind around the spool provides adequate restraint to keep the line from being pulled out of the hole when additional turns of line are wound over the first layer of line on the hub of the spool.
However, as the amount of line remaining on the spool becomes shorter and shorter during use, there is less and less force holding the line end or ends in the holes in the hub, and eventually the forces acting on the line will cause it to come out of the hole or holes. While the length of line remaining when the end comes out of the holes will vary to some extent, this amount can represent a significant waste, particularly for commercial users of such equipment. Often, two feet or more of line is wasted for each line on the spool, or a total of at least four feet in the case of spools with two projecting line ends.
Some effort in the past has been made to overcome this drawback, such as shown in U.S. Pat. No. 4,195,408 issued to Palmieri et al, wherein a single length of line is doubled and the two ends are passed outwardly from the central opening of the hub so as to leave a U-shaped loop on the interior of the hub. However, the mere provision of two closely spaced holes in this manner leaves a weak spot between the two holes. Since most spools of this type are molded from plastic material, this weak point may be easily broken, so that the spool becomes useless.
In addition, because of the tight bend in the line at the loop, the line itself may be weakened at the bend. Further, the line usually is rather thick, on the order of 1-1.5 mm, and because of this thickness, it cannot be bent very tightly and thus projects into the central opening of the hub. In turn, this tends to interfere with the mounting of the spool on the clutch.
Accordingly, a primary object of the present invention is to provide a replacement spool for nylon line type vegetation trimmers which overcomes the disadvantages of prior art spools.
Another object of this invention is to provide a replacement spool for such vegetation cutters which enables use of the line down to the point where only a short, essentially unusable length of such line remains on the spool.
Still a further object of this invention is to provide a replacement spool for line vegetation cutters which is of greater strength at the line attachment point than in the prior art.
Yet another object of the present invention is to provide an improved replacement spool which may be readily used with many existing vegetation cutters.
These and other objects and advantages of this invention will become apparent upon consideration of the following specification and claims when taken together with the accompanying drawings.